It’s DNA all over again

October 23, 2008

Perhaps you haven't heard: You can now buy test kits over the counter that are touted as a way to get personalized information about your genes - your DNA that is. Is this a smart, relatively inexpensive way to obtain insight into your DNA makeup, or would it be wiser to treat that information to read DN/A - Definitely Not Applicable?

Here's some thought-provoking background on the topic that may help you decide for yourself. Essentially, such testing can be categorized into two types: the large majority of genetic tests only available through your physician and the presently available products marketed directly to consumers by two companies.

The obvious question is: Are you capable of providing the counseling and information about the meaning and results required for proper utilization of this information without the intervention of your doctor? MedPage's North American Correspondent Michael Smith advised - not so, when he commented "Much like investing on Wall Street, buying personalized genetic information can represent ownership of an expensive piece of paper with little or no value." Apparently, when reviewing Smith's article, Don F. Zaleznik, MD, Associate Clinical Professor of Medicine at Harvard Medical School, found no reason to disagree with this objection.

Suppose we put this discussion a bit more into perspective. Presently, four companies insist that currently available OTC products will aid treatment for their intended targets.

So, what targets are we talking about? Well, actually, there is only one at this point. It involves an enzyme called cytochrome P450, which is involved through its effect on serotonin reuptake inhibitors.

You may not have heard yet, but I'm certain that you soon shall; Serotonin is involved in such mental variations as might occur in depression not due to some psychosis. Is there reason to believe that a depressed patient will benefit from self-testing for this genetic variation? A recent review of 37 published papers concluded as follows:

These tests are both sensitive and specific.

There was no evidence that testing in adults entering treatment for non-psychotic depression leads to improvement in outcomes, compared with not testing, or that testing influences treatment management decisions that could alter outcomes.

However, no evidence of harm associated with testing or with subsequent management could be noted.

Obviously, there is another side to this argument. Kristine Ashcraft expressed the most compelling, from my own point of view, in a commentary on April 4, 2008 about an article published in Science. She concludes, after taking issue with the authors about quoting out of context from the Web site of one of the companies, Genelex, and expressing the usefulness over a lifetime of genetic information, that "clinicians and patients who find this information useful should have access to it."

Frankly, it seems apparent to me, that opinions with regard to the usefulness of such tests by untrained patients are uniquely colored by the profit motive, be it monetary or strictly scientific. Furthermore, what would you want to learn from the results gained from testing yourself? According to the companies supplying tests for the public, their usefulness lies in their ability to evaluate the effect of drugs that you are taking.

Certainly, you would like to know whether the dose that has been prescribed for you is in line with your body's ability to utilize that dosage. Just think about how fantastic it would be if you could eliminate one of the most important reasons for ending up with side effects that might actually be as bad or worse than the original symptoms of your condition. On the other hand, how sure can you be that changing your dose levels on your own might not seriously effect the efficiency of your medication and even create more severe adverse affects?

Evidently, the future is upon us. Just be certain to look to the right, left, front and back before you leap. By all means, when you do decide to leap, be sure to CYA.